Add navigation and copy functionality to move dialog

- Add breadcrumb navigation to move dialog for folder navigation
- Add 'Copy' button alongside 'Move' button in the dialog
- Implement copyFile and copyFolder functions in fileOps
- Add copy handler for batch operations
- Add CSS styles for btn-outline button (light and dark mode)
- Add translations for new dialog strings

fix: properly show home folder contents in move dialog

- Use effectiveParentId for all checks and rendering
- Show 'Select this folder' option for home folder
- Only show 'go to parent' when breadcrumb has items (navigated into subfolders)
fix: improve move dialog UX

- Hide breadcrumb at home folder level (not needed)
- Only show 'Select this folder' option after navigating into subfolders
- Show 'no subfolders' message when there are no folders to navigate
- Properly display subfolders for navigation

static/js/app/ui.js

@@ -121,6 +121,7 @@ const ui = {
                     </div>
                     <div class="rename-dialog-buttons">
                         <button class="btn btn-secondary" id="move-cancel-btn" data-i18n="actions.cancel">Cancel</button>
+                        <button class="btn btn-outline" id="copy-confirm-btn" data-i18n="actions.copy">Copy</button>
                         <button class="btn btn-primary" id="move-confirm-btn" data-i18n="actions.move_to">Move</button>
                     </div>
                 </div>